000 AXNT20 KNHC 212352 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST MON DEC 21 2015 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...SPECIAL FEATURE... THE PRESSURE GRADIENT GENERATED BETWEEN THE HIGH PRESSURE CURRENTLY CENTERED OVER THE ATLANTIC AND LOWER PRESSURES OVER THE NORTHERN PORTION OF SOUTH AMERICA IS SUPPORTING GALE FORCE WINDS ACROSS THE S-CENTRAL CARIBBEAN FROM 11N-12N BETWEEN 72W- 75W. SEAS UP TO 17 FT ARE EXPECTED IN THIS AREA. THE GALE FORCE WINDS WILL CONTINUE OVER THIS AREA THROUGH THE NEXT 48 HOURS. FOR MORE INFORMATION PLEASE REFER TO THE HIGH SEAS FORECAST PRODUCT UNDER AWIPS/WMO HEADER MIAHSFAT2/FZNT02 KNHC. ...ITCZ/MONSOON TROUGH... THE ITCZ AXIS EXTENDS FROM 04N10W TO 04N30W TO 00N50W. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM OF EITHER SIDE OF THE ITCZ AXIS MAINLY E OF 31W. ...DISCUSSION... GULF OF MEXICO... A DIFFLUENT FLOW ALOFT IS BRINGING UPPER-LEVEL MOISTURE ACROSS THE NORTHERN PORTION OF THE BASIN MAINLY N OF 23N SUPPORTING SCATTERED MODERATE CONVECTION ACROSS THIS AREA. AT LOWER LEVELS...A SURFACE RIDGE EXTENDS W FROM THE W-CENTRAL ATLANTIC ACROSS THE GULF. SCATTEROMETER DATA DEPICTS A GENTLE TO MODERATE SE FLOW ACROSS THE WESTERN AND CENTRAL GULF W OF 88W WHILE MODERATE TO FRESH E WINDS PREVAIL E OF 88W INCLUDING THE FLORIDA STRAITS. OVER THE NEXT 24 HOURS...A FRONTAL BOUNDARY WILL APPROACH THE TEXAS COASTLINE ENHANCING CONVECTION ACROSS THE NW GULF WATERS. CARIBBEAN SEA... A PRESSURE GRADIENT BETWEEN THE HIGH PRESSURE ACROSS THE ATLANTIC AND LOWER PRESSURES ACROSS NORTHERN S AMERICA IS SUPPORTING GALE FORCE WINDS ACROSS THE S-CENTRAL CARIBBEAN BETWEEN 72W-75W. PLEASE REFER TO THE SECTION ABOVE FOR MORE DETAILS. MODERATE TO FRESH TRADES PREVAIL ACROSS THE REMAINDER OF THE BASIN. SHALLOW MOISTURE TRANSPORTED BY THE TRADES IS GENERATING LOW-TOPPED SHOWERS ACROSS THE WHOLE BASIN. AT UPPER LEVELS...A TROUGH EXTENDS FROM THE BAHAMAS ACROSS E-CENTRAL CUBA TO HONDURAS. CLOUDINESS AND SCATTERED LIGHT TO MODERATE CONVECTION IS OBSERVED E OF THIS TROUGH AFFECTING E CUBA...THE WINDWARD PASSAGE...JAMAICA...AND THE NW CARIBBEAN WATERS N OF 18N AND W OF 74W. EXPECT A SIMILAR WEATHER PATTERN OVER THE NEXT 24 HOURS. ...HISPANIOLA... AN UPPER-LEVEL TROUGH IS OVER E-CENTRAL CUBA SUPPORTING ISOLATED CONVECTION ACROSS PORTIONS OF THE WINDWARD PASSAGE AND HAITI. THIS PATTERN IS EXPECTED TO CONTINUE OVER THE NEXT 24 HOURS THEREFORE...ISOLATED CONVECTION IS STILL POSSIBLE. ATLANTIC OCEAN... A BROAD SURFACE RIDGE PREVAILS ACROSS THE BASIN ANCHORED BY A 1036 MB HIGH CENTERED NEAR 35N56W. S OF THIS HIGH...A FRONTAL SYSTEM WAS ANALYZED AS A STATIONARY FRONT FROM 27N70W TO 26N59W...THEN AS A COLD FRONT FROM THAT POINT TO 31N42W. ISOLATED CONVECTION IS OBSERVED ALONG THESE BOUNDARIES. S OF THIS BOUNDARY...AN UPPER-LEVEL TROUGH IS ENHANCING ISOLATED MODERATE CONVECTION ACROSS BAHAMAS MAINLY S OF 25N BETWEEN 69W- 75W. EXPECT OVER THE NEXT 24 HOURS FOR THE COLD FRONT TO CONTINUE MOVING E WITH ISOLATED CONVECTION. THE SURFACE RIDGE WILL PREVAIL N OF THE FRONT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ ERA